1. Field of the Invention
This invention relates generally to a durable storage container used for aging wine. More particularly, this invention relates to a composite wine container constructed of a metal drum with wood end covers in which the aging of wine is controllable and efficient.
2. Description of the Prior Art
Most quality wines are aged in oak barrels, in which the desirable sensory characteristics of the wine such as bouquet, color and flavor are largely obtained from the oxidation and extraction reactions that occur during the aging of the wine. To achieve reproducible results using traditional wine barrels, it is essential to control the parameters of the oxidation and extraction reactions that take place during the aging period. Unwanted oxidation is detrimental to the quality of wine and it is well known to minimize the rate of such oxidation during the production and aging of quality wines by protecting such wines against excessive exposure to air. However, because of the penetration of air into the wood by diffusion and the periodic loss of wine volume due to seepage, sampling and the like, all previous efforts to control the rate of oxidation in permeable wooden containers have proven to be commercially inefficient and costly.
Mostly expensive red wines and certain white wines of greater quality are required to be aged slowly, generally over a period of one to two years, depending upon the acceptable amounts of a tannin flavor which is imparted by the wood phenolics to the specified wine. However, with continuous use of wooden wine barrels over extended periods, the inner surfaces become contaminated with wine residue and the much sought after wood flavor becomes less and less available. Moreover, oak wine barrels, which are reused three to six times each, impart varying sensory characteristics to the wine according to the age of the barrel, making reproducibility from batch to batch difficult. In any event, oak barrels usually lose their flavor after about five years and most wineries discard these barrels shortly after this period of use. Also, conventional wine barrels when not in use are subject to attack by certain types of bacteria or fungi and frequently must be treated with suitable chemicals to avoid any serious contamination. Although this chemical treatment increses the life of the wood barrels, it is a time-consuming and tedious operation and may even degrade the taste of the wine if any residual chemicals are not thoroughtly removed. Accordingly, it sometimes becomes necessary to discard not only used barrels, but contaminated wooden wine barrels as well. However, in a large winery where there are a costly number of barrels made by conventional cooperage methods, the replacement cost involved becomes economically prohibitive.
Various types of wine aging containers made essentially from nonporous plastic materials or glass are found on the market today. However, these impervious containers are particularly adapted for use in home wine-making kits and are not suitable for the production of quality wines in large quantities. Moreover, the preferable flavor imparted by wooden containers is loss in these usually disposable containers and the reproducibility of other sensory properties of the wine is almost impossible to achieve.
A particular type of wine cask suitable for containing wine which is required to be aged in wood is described in U.S. Pat. No. 4,813,565 to Croser (issued Mar. 21, 1989). This patent discloses a wine cask having a circular metal base and a circular metal cover, and a plurality of wood staves extending in an axial direction therebetween. Clamp bands retain the staves in a circumferential configuration and tension clamp bands extending longitudinally along the exterior of the wine cask place the staves under compression and retain the metal base and end covers in position. Since only the base and end covers are made from relatively inexpensive metal, the overall cost of the patented wine container is not substantially reduced due to the excessive usage of the wood staves. Moreover, it is apparent that the clamp bands must be continuously adjusted to accommodate the normal contraction and expansion of the staves. Failure to make such time consuming adjustments could cause leaks which may result in harmful oxidation and spoilage of the wine batch. Thus, the Croser wine cask fails to eliminate the aforementioned disadvantages inherent in substantially wooden wine containers.